Writing instrument



FIG. 1 is a left side perspective view taken from the side and below showing our new design;

FIG. 2 is a front elevational view, the rear elevational view being a mirror image thereof;

FIG. 3 is a left side elevational view, the right side elevational view being a mirror image thereof;

FIG. 4 is a top plan view thereof; and,

FIG. 5 is a bottom plan view thereof. 

The ornamental design for a “writing instrument”, as shown and described. 